Latest content added for Digital Library Collection: National Advisory Committee for Aeronautics (NACA)https://digital.library.unt.edu/explore/collections/NACA/browse/?sort=added_d&fq=untl_decade:1940-19492015-02-26T16:50:55-06:00UNT LibrariesThis is a custom feed for browsing Digital Library Collection: National Advisory Committee for Aeronautics (NACA)Some Recent Contributions to the Study of Transition and Turbulent Boundary Layers2015-02-26T16:50:55-06:00https://digital.library.unt.edu/ark:/67531/metadc172454/<p><a href="https://digital.library.unt.edu/ark:/67531/metadc172454/"><img alt="Some Recent Contributions to the Study of Transition and Turbulent Boundary Layers" title="Some Recent Contributions to the Study of Transition and Turbulent Boundary Layers" src="https://digital.library.unt.edu/ark:/67531/metadc172454/small/"/></a></p><p>None</p>Considerations of the Total Drag of Supersonic Airfoil Sections2015-02-26T16:50:55-06:00https://digital.library.unt.edu/ark:/67531/metadc172466/<p><a href="https://digital.library.unt.edu/ark:/67531/metadc172466/"><img alt="Considerations of the Total Drag of Supersonic Airfoil Sections" title="Considerations of the Total Drag of Supersonic Airfoil Sections" src="https://digital.library.unt.edu/ark:/67531/metadc172466/small/"/></a></p><p>The results of calculations of the viscous and pressure drags of some two-dimensional supersonic airfoils at zero lift are presented. The results indicate that inclusion of viscous drag alters many previous results regarding the desirability of certain airfoil shapes for securing low drags at supersonic speeds. At certain Reynolds and Mach numbers, for instance, a circular-arc airfoil may theoretically have less drag than the previously advocated symmetrical wedge-shape profile; although under different conditions, the circular-arc airfoil may have a higher drag.</p>Tables and Charts of Flow Parameters Across Oblique Shocks2014-09-25T20:32:43-05:00https://digital.library.unt.edu/ark:/67531/metadc172508/<p><a href="https://digital.library.unt.edu/ark:/67531/metadc172508/"><img alt="Tables and Charts of Flow Parameters Across Oblique Shocks" title="Tables and Charts of Flow Parameters Across Oblique Shocks" src="https://digital.library.unt.edu/ark:/67531/metadc172508/small/"/></a></p><p>Shock-wave equations have been evaluated for a range of Mach number in front of the shock from 1.05 to 4.0. Mach number behind the shock, pressure ratio, derivation of flow, and angle of shock are presented on charts. Values are also included for density ratio and change in entropy.</p>Two-Dimensional Irrotational Transonic Flows of a Compressible Fluid2014-09-25T20:32:43-05:00https://digital.library.unt.edu/ark:/67531/metadc172480/<p><a href="https://digital.library.unt.edu/ark:/67531/metadc172480/"><img alt="Two-Dimensional Irrotational Transonic Flows of a Compressible Fluid" title="Two-Dimensional Irrotational Transonic Flows of a Compressible Fluid" src="https://digital.library.unt.edu/ark:/67531/metadc172480/small/"/></a></p><p>The methods of NACA TN No. 995 have been slightly modified and extended in include flows with circulation by considering the alteration of the singularities of the incompressible solution due to the presence of the hypergeometric functions in the analytic continuation of the solution. It was found that for finite Mach numbers the only case in which the nature of the singularity can remain unchanged is for a ratio of specific heats equal to -1. From a study of two particular flows it seems that the effect of geometry cannot be neglected, and the conventional "pressure-correction" formulas are not valid, even in the subsonic region if the body is thick, especially if there is a supersonic region in the flow.</p>Charts for the Computation of Equilibrium Composition of Chemical Reactions in the Carbon-Hydrogen-Nitrogen System at Temperatures from 2000 to 5000 Degrees K2014-09-25T20:32:43-05:00https://digital.library.unt.edu/ark:/67531/metadc100821/<p><a href="https://digital.library.unt.edu/ark:/67531/metadc100821/"><img alt="Charts for the Computation of Equilibrium Composition of Chemical Reactions in the Carbon-Hydrogen-Nitrogen System at Temperatures from 2000 to 5000 Degrees K" title="Charts for the Computation of Equilibrium Composition of Chemical Reactions in the Carbon-Hydrogen-Nitrogen System at Temperatures from 2000 to 5000 Degrees K" src="https://digital.library.unt.edu/ark:/67531/metadc100821/small/"/></a></p><p>Charts are provided for the estimation and progressive adjustment of two independent variables on which the calculations are based. Additional charts are provided for the graphical calculation of the composition.</p>Effect of the performance of a turbosupercharged engine of an exhaust-gas-to-air heat exchanger for thermal ice prevention2014-03-30T18:00:15-05:00https://digital.library.unt.edu/ark:/67531/metadc279594/<p><a href="https://digital.library.unt.edu/ark:/67531/metadc279594/"><img alt="Effect of the performance of a turbosupercharged engine of an exhaust-gas-to-air heat exchanger for thermal ice prevention" title="Effect of the performance of a turbosupercharged engine of an exhaust-gas-to-air heat exchanger for thermal ice prevention" src="https://digital.library.unt.edu/ark:/67531/metadc279594/small/"/></a></p><p>None</p>The calculation of span LCAD distributions of swept-back wings2014-03-30T18:00:15-05:00https://digital.library.unt.edu/ark:/67531/metadc279443/<p><a href="https://digital.library.unt.edu/ark:/67531/metadc279443/"><img alt="The calculation of span LCAD distributions of swept-back wings" title="The calculation of span LCAD distributions of swept-back wings" src="https://digital.library.unt.edu/ark:/67531/metadc279443/small/"/></a></p><p>Span load distributions of swept-back wings have been calculated. The method used was to replace the wing with a bound vortex at the quarter-chord line and to calculate the downwash due to the system of bound and trailing vortices to conform at the three-quarter-chord line to the slope of the flat-plate wing surface. Results are given for constant-chord and 5:1 tapered plan forms, for sweep-back angles of 0 degrees, 30 degrees, and 45 degrees, and for aspect ratios of 3, 6, and 9. Some comments on the stalling of swept-back wings are included.</p>Comparison of Vee-Type and Conventional Tail Surfaces in Combination with Fuselage and Wing in the Variable-Density Tunnel2014-03-30T18:00:15-05:00https://digital.library.unt.edu/ark:/67531/metadc279435/<p><a href="https://digital.library.unt.edu/ark:/67531/metadc279435/"><img alt="Comparison of Vee-Type and Conventional Tail Surfaces in Combination with Fuselage and Wing in the Variable-Density Tunnel" title="Comparison of Vee-Type and Conventional Tail Surfaces in Combination with Fuselage and Wing in the Variable-Density Tunnel" src="https://digital.library.unt.edu/ark:/67531/metadc279435/small/"/></a></p><p>The pitching and the yawing moments of a vee-type and a conventional type of tail surface were measured. The tests were made in the presence of a fuselage and a wing-fuselage combination in such a way as to determine the moments contributed by the tail surfaces. The results showed that the vee-type tail tested, with a dihedral angle of 35.3 deg, was about 71 percent as effective in pitch as the conventional tail and had a yawing-moment to pitching-moment ratio of 0.3. The conventional tail, the panels of which were all congruent to those of the vee-type tail, had a yawing-moment to pitching-moment ratio of 0.48. These ratios are in fair agreement with values calculated by methods shown in this and previous reports. The values of the measured moments were reduced from 15 to 25 percent of the calculated value by fuselage interference.</p>Methods of analyzing wind-tunnel data for dynamic flight conditions2014-03-30T18:00:15-05:00https://digital.library.unt.edu/ark:/67531/metadc279446/<p><a href="https://digital.library.unt.edu/ark:/67531/metadc279446/"><img alt="Methods of analyzing wind-tunnel data for dynamic flight conditions" title="Methods of analyzing wind-tunnel data for dynamic flight conditions" src="https://digital.library.unt.edu/ark:/67531/metadc279446/small/"/></a></p><p>The effects of power on the stability and the control characteristics of an airplane are discussed and methods of analysis are given for evaluating certain dynamic characteristics of the airplane that are not directly discernible from wind-tunnel tests alone. Data are presented to show how the characteristics of a model tested in a wind tunnel are affected by power. The response of an airplane to a rolling and a yawing disturbance is discussed, particularly in regard to changes in wing dihedral and fin area. Solutions of the lateral equations of motion are given in a form suitable for direct computations. An approximate formula is developed that permits the rapid estimation of the accelerations produced during pull-up maneuvers involving abrupt elevator deflections.</p>Effects of some present-day airplane design trends on requirements for lateral stability2014-03-30T18:00:15-05:00https://digital.library.unt.edu/ark:/67531/metadc279598/<p><a href="https://digital.library.unt.edu/ark:/67531/metadc279598/"><img alt="Effects of some present-day airplane design trends on requirements for lateral stability" title="Effects of some present-day airplane design trends on requirements for lateral stability" src="https://digital.library.unt.edu/ark:/67531/metadc279598/small/"/></a></p><p>None</p>